The present invention is related to ink valves, ink delivery systems, and a method that limit the air transmission rates into an ink supply and/or ink tube of an ink delivery system.
During the process associated with printing in an ink delivery system, an ink supply source delivers ink to a printhead for ejection onto a print media. The ink supply exerts a large negative pressure on a printhead regulator. Moreover, as ink is moved from the ink supply source to the printhead air can permeate and be absorbed into intermediate components of the ink delivery system. Air absorption causes air to excessively accumulate in the printhead, such that when too much air has accumulated little to no ink will be ejected from the printhead. Further, a pressure regulator within the printhead can malfunction from too much air absorption causing the printhead to leak ink, which can degrade print quality.
Accordingly, various techniques have attempted to create better seals for the components and/or connections used within ink delivery systems in order to minimize the amount of air absorption or air transmission within the systems. One technique uses a check valve that is interposed between the ink supply source and the printhead. However, a check valve does not permit a good quality seal that minimizes back flow from a printhead. Another technique uses a pinch valve that is interposed between the ink supply source and the printhead. Yet, with a pinch valve it is difficult to pinch materials in the ink delivery system that are good air barriers. Typically, pinch valve techniques use materials for components of the ink delivery system that have low compression properties with high air transmission properties.
Therefore, there is a need for improved ink valves, ink delivery systems, and techniques with low air transmission rates. Moreover, the materials for the various components of the ink valves and the ink delivery systems should be durable materials that to not degrade or do not introduce chemicals into the ink supply after extended exposure to ink.
Briefly and in general terms, an ink valve, in various embodiments of the present invention, includes an inlet for receiving a portion of a supply of ink from an ink supply source. Furthermore, the valve includes an outlet for ejecting ink to a printhead. Ink is gathered into a central cavity or chamber from the inlet. The central cavity is segmented into two regions by an Elastomer material. The first region includes a seal that is located on the Elastomer material and adapted to close and/or plug the inlet in order to stop and/or permit the flow of ink into the central cavity. The second region includes a mechanism for applying and releasing a force that moves the seal away from or toward the inlet.